Tutoial - Part 2 TutoRial - Part 2

Marine Ecosystem Dynamics - 2024

Pipes

Pipes, expressed as %>% or |>, are very useful and make our code clearer. Using pipes, our data flow from one function to another.

Exercises

• Rewrite these chunks of code using the pipes

sum(c(2.2,4.1,2,pi))

Solution

c(2.2,4.1,2,pi) |> sum()
# OR
c(2.2,4.1,2,pi) %>% sum()

round(sum(c(2.2,4.1,2,pi)))

Solution

c(2.2,4.1,2,pi) |> sum() |> round()
# OR
c(2.2,4.1,2,pi) %>% sum() %>% round()

round(sum(c(2.2,4.1,2,pi)), digits = 3)

Solution

c(2.2,4.1,2,pi) |> sum() |> round(digits = 3)
# OR
c(2.2,4.1,2,pi) %>% sum() %>% round(digits = 3)

Tidy the data with tidyr

As seen in the slides, a tidy table has:

1. Each variable in its own column
2. Each observation in its own row

To reach this, tidyr has 4 key functions:

1. pivot_longer
2. pivot_wider
3. unite
4. separate

Exercises

• If this is not done yet, download the dataset zooplankton_seasonality.csv

• Import the dataset in your environment

• Is this dataset a tidy dataset?

Solution

First 6 rows of the dataset zooplankton_seasonality

Month_abb	Year	Station	Coordinates	Group	Taxa	Biomass
Jan	2009	BY15	20.05000/57.33333	Copepoda	Acartia	6.650319
Jan	2009	BY31	18.23333/58.58812	Copepoda	Acartia	1.816994
Jan	2009	BY5	15.98333/55.25000	Copepoda	Acartia	5.562097
Jan	2009	BY15	20.05000/57.33333	Copepoda	Centropages	5.738562
Jan	2009	BY31	18.23333/58.58812	Copepoda	Centropages	1.228759
Jan	2009	BY5	15.98333/55.25000	Copepoda	Centropages	14.405224

Each variable has its own column
Each variable has its own row
Coordinates has 2 values

• Separate the column Coordinates in 2 news columns: Longitude and Latitude

Solution

First 6 rows of the dataset zooplankton_seasonality with the column Coordinates separated as Longitude and Latitude

Month_abb	Year	Station	Longitude	Latitude	Group	Taxa	Biomass
Jan	2009	BY15	20.05000	57.33333	Copepoda	Acartia	6.650319
Jan	2009	BY31	18.23333	58.58812	Copepoda	Acartia	1.816994
Jan	2009	BY5	15.98333	55.25000	Copepoda	Acartia	5.562097
Jan	2009	BY15	20.05000	57.33333	Copepoda	Centropages	5.738562
Jan	2009	BY31	18.23333	58.58812	Copepoda	Centropages	1.228759
Jan	2009	BY5	15.98333	55.25000	Copepoda	Centropages	14.405224

library(tidyr)
zooplankton |> separate(Coordinates, into = c("Longitude", "Latitude"), sep = "/")